/// <inheritdoc/>
public void DecodeFromStream(Stream stream, Image image)
{
if (!this.HasNV12Header(stream))
{
throw new ArgumentException("Stream does not appear to be NV12-encoded (missing header).");
}
stream.Position = 4; // skip header
// decode NV12
var width = image.Width;
var height = image.Height;
int startUV = width * height;
int strideUV = width;
var size = (int)(width * height * 1.5 + 0.5); // 12-bit/pixel
using var sharedData = SharedArrayPool <byte> .GetOrCreate(size);
var data = sharedData.Resource;
stream.Read(data, 0, size);
unsafe
{
var buffer = (byte *)image.UnmanagedBuffer.Data;
for (int i = 0; i < height; i++)
{
var p = buffer + (i * 4 * width);
int row = i * width;
var startUVrow = startUV + ((i / 2) * strideUV);
for (int j = 0; j < width; j++)
{
var y = data[row + j] - 16;
var uindex = startUVrow + (2 * (j / 2));
var u = data[uindex] - 128;
var v = data[uindex + 1] - 128;
var yy = 1.164383 * y;
var b = yy + (2.017232 * u);
var g = yy - (0.812968 * v) - (0.391762 * u);
var r = yy + (1.596027 * v);
*p++ = (byte)Math.Max(0, Math.Min(255, b + 0.5));
*p++ = (byte)Math.Max(0, Math.Min(255, g + 0.5));
*p++ = (byte)Math.Max(0, Math.Min(255, r + 0.5));
*p++ = 0xff; // alpha
}
}
}
}
public void SharedArrayPoolTest()
{
// allocate and release an array of size 10
var int10 = SharedArrayPool <int> .GetOrCreate(10);
Assert.AreEqual(10, int10.Resource.Length);
object ref10 = int10.Resource; // capture the underlying array reference
int10.Dispose();
// allocate and release an array of size 20
var int20 = SharedArrayPool <int> .GetOrCreate(20);
Assert.AreEqual(20, int20.Resource.Length);
object ref20 = int20.Resource; // capture the underlying array reference
int20.Dispose();
// request another array of size 10 without releasing
int10 = SharedArrayPool <int> .GetOrCreate(10);
Assert.AreEqual(10, int10.Resource.Length);
Assert.AreSame(ref10, int10.Resource); // verify recycled resource
// request another array of size 20 without releasing
int20 = SharedArrayPool <int> .GetOrCreate(20);
Assert.AreEqual(20, int20.Resource.Length);
Assert.AreSame(ref20, int20.Resource); // verify recycled resource
// allocate another array of size 20 without releasing
var int20_2 = SharedArrayPool <int> .GetOrCreate(20);
Assert.AreEqual(20, int20_2.Resource.Length);
Assert.AreNotSame(ref20, int20_2.Resource); // not recycled
// allocate another array of size 10 without releasing
var int10_2 = SharedArrayPool <int> .GetOrCreate(10);
Assert.AreEqual(10, int10_2.Resource.Length);
Assert.AreNotSame(ref10, int10_2.Resource); // not recycled
// release all instances
int10.Dispose();
int20.Dispose();
int10_2.Dispose();
int20_2.Dispose();
}
/// <inheritdoc/>
public unsafe void Start(Action <DateTime> notifyCompletionTime)
{
// notify that this is an infinite source component
notifyCompletionTime(DateTime.MaxValue);
this.camera = new MediaCaptureInternal(this.configuration.DeviceId);
this.camera.Open();
var isFormatSupported = false;
foreach (var format in this.camera.SupportedPixelFormats())
{
if (format.Pixels == this.configuration.PixelFormat)
{
this.camera.SetVideoFormat(this.configuration.Width, this.configuration.Height, format);
isFormatSupported = true;
}
}
if (!isFormatSupported)
{
throw new ArgumentException($"Pixel format {this.configuration.PixelFormat} is not supported by the camera");
}
var current = this.camera.GetVideoFormat();
if (current.Width != this.configuration.Width || current.Height != this.configuration.Height)
{
throw new ArgumentException($"Width/height {this.configuration.Width}x{this.configuration.Height} is not supported by the camera");
}
this.camera.OnFrame += (_, frame) =>
{
var originatingTime = this.pipeline.GetCurrentTime();
if (this.Raw.HasSubscribers)
{
var len = frame.Length;
using (Shared <byte[]> shared = SharedArrayPool <byte> .GetOrCreate(len))
{
Marshal.Copy(frame.Start, shared.Resource, 0, len);
this.Raw.Post(shared, originatingTime);
}
}
if (this.Out.HasSubscribers)
{
using (var sharedImage = ImagePool.GetOrCreate(this.configuration.Width, this.configuration.Height, PixelFormat.BGR_24bpp))
{
if (this.configuration.PixelFormat == PixelFormatId.BGR24)
{
sharedImage.Resource.CopyFrom((IntPtr)frame.Start);
this.Out.Post(sharedImage, this.pipeline.GetCurrentTime());
}
else if (this.configuration.PixelFormat == PixelFormatId.YUYV)
{
// convert YUYV -> BGR24 (see https://msdn.microsoft.com/en-us/library/ms893078.aspx)
var len = (int)(frame.Length * 1.5);
using (Shared <byte[]> shared = SharedArrayPool <byte> .GetOrCreate(len))
{
var bytes = shared.Resource;
var pY = (byte *)frame.Start.ToPointer();
var pU = pY + 1;
var pV = pY + 3;
for (var i = 0; i < len;)
{
int y = (*pY - 16) * 298;
int u = *pU - 128;
int v = *pV - 128;
int r = (y + (409 * v) + 128) >> 8;
int g = (y - (100 * u) - (208 * v) + 128) >> 8;
int b = (y + (516 * u) + 128) >> 8;
bytes[i++] = (byte)((r < 0) ? 0 : ((r > 255) ? 255 : r));
bytes[i++] = (byte)((g < 0) ? 0 : ((g > 255) ? 255 : g));
bytes[i++] = (byte)((b < 0) ? 0 : ((b > 255) ? 255 : b));
pY += 2;
y = (*pY - 16) * 298;
r = (y + (409 * v) + 128) >> 8;
g = (y - (100 * u) - (208 * v) + 128) >> 8;
b = (y + (516 * u) + 128) >> 8;
bytes[i++] = (byte)((r < 0) ? 0 : ((r > 255) ? 255 : r));
bytes[i++] = (byte)((g < 0) ? 0 : ((g > 255) ? 255 : g));
bytes[i++] = (byte)((b < 0) ? 0 : ((b > 255) ? 255 : b));
pY += 2;
pU += 4;
pV += 4;
}
sharedImage.Resource.CopyFrom(bytes);
this.Out.Post(sharedImage, originatingTime);
}
}
}
}
#if TEST_DROPPED_FRAMES
System.Threading.Thread.Sleep(1000); // for testing dropped frames
#endif // TEST_DROPPED_FRAMES
frame.Dispose(); // release back to driver!
};
this.camera.StreamBuffers();
}
